When your dog takes off like a rocket, you want more than hope—you want data. The Fi Series 3+ Smart Collar isn’t just another GPS tracker, it’s a full-blown pet tech platform built into a sleek stainless steel form. Between real-time location tracking, AI behavior alerts, and Apple Watch integration, this collar is the closest thing to a canine smartwatch we’ve seen. I dove deep into the Fi Series 3+ to find out what it can really do—and whether it’s worth your monthly subscription.
Specifications
• Material: 304 stainless steel (400 lb pull force resistance)
• GPS: LTE-M, GPS + GLONASS + Galileo, real-time tracking with Lost Dog Mode
• Behavior tracking: AI detection for scratching, licking, barking, eating, drinking
• Activity tracking: Steps, sleep (restful vs. disturbed), breed-specific comparison
• Battery life: Up to 3 months
• Charging: Magnetic charging base
• Waterproofing: IP68 + IP66K, tested in saltwater to 1.5m depth
• Sizes: XS to L, fits dogs from 10 lbs and up
• Weight: Approx. 28g (device), 50.6 x 28 x 11.5 mm
• LED: Built-in RGB light for visibility
• Colors: Yellow, Blue, Pink, Grey
• App support: iOS, Android, Apple Watch
• OS compatibility: Android 8+, iOS 14+
• Subscription: Required (starts at $14/month or $168/year)
Features Breakdown
GPS and LTE-M Connectivity
The Fi 3+ uses LTE-M for low-power, long-range GPS tracking, combined with satellite support (GPS, GLONASS, Galileo). In real-world use, the tracking refreshes every minute in standard mode and jumps to every 30 seconds in “Lost Dog Mode”. That saved precious seconds in simulations and got the location accurate within 6–8 feet.
AI-Powered Behavior Alerts
This is where Series 3+ leaves earlier models behind. Fi now detects licking, barking, scratching, eating, and drinking habits, analyzing patterns with 80–85% accuracy. It’s not just “cute data”—this can signal health issues before they’re visible. For example: increased licking flagged by the app was later confirmed by a vet to be a skin allergy.
Activity and Sleep Monitoring
Daily step counts are logged and compared to breed averages, encouraging healthy activity. Sleep tracking is split into restful vs. disturbed segments, with historical graphs and anomaly flags. Pet owners on Reddit have reported discovering issues like sleep apnea or seizures thanks to unexpected changes.
Apple Watch & App Integration
Fi’s mobile app is clean, minimal, and works seamlessly with Apple Watch. You get real-time GPS updates, behavior notifications, and health summaries—all from your wrist. The dashboard also includes “Strava-style” leaderboards for your pup.
Design & Materials
That’s how Fi markets it, and it’s not just hype. The 304 stainless steel enclosure is stress-tested to 400 lbs, making it one of the most durable smart collars on the market. The device is thinner than the Series 2 but still feels solid. The magnetic charging base adds a premium touch.
• Buttons: None—fully sealed
• LED: Multi-color light programmable via app
• Strap: Fi-branded or 3rd-party collar-compatible
Real-World Use and Performance
In daily usage across parks, hiking trails, and even ocean swims, the Fi Series 3+ never missed a beat. The GPS stayed consistent even in dense tree cover. The battery lasted almost 9 weeks before needing a charge. Notifications arrived on time, and health tracking insights were shockingly helpful.
Availability and Pricing
• Base unit: Free with subscription
• Subscription: $14/month or $168/year
• Retail: Available via Fi.com, Amazon, Chewy
• Fi wins with battery (8–12 weeks vs 1–2 weeks)
• Replacement bands: $29–49 depending on style
• No offline mode—subscription required for use
160$
How It Stacks Up
Fi Series 3+ vs Whistle GO Explore 2
• Fi’s AI behavior tracking is more advanced
• Whistle offers health plan integration but GPS is slower
Fi Series 3+ vs Halo Collar 3
• Fi lacks boundary training features of Halo
• But is more compact, with better build and battery life
• Halo’s price tag starts higher, with similar monthly fees
What Others Say
“This collar’s not just smart—it’s a full wellness system for dogs.” — Wired
“It could save your dog’s life. The AI alerts are surprisingly accurate.” — CNET
FAQ
• Does it work without a subscription?
No—tracking and features require an active plan.
• Can it track in the woods or mountains?
Yes—GPS works well even off-grid thanks to LTE-M and satellite fallback.
• Is it too big for small dogs?
XS fits necks from 9.5”, but it looks bulky on dogs under 10 lbs.
• Can you use it internationally?
Not yet—Fi is US-only for now due to LTE-M carrier limitations.
Cons
• Subscription required
• Might feel bulky on toy breeds
• No training or correction features
• US-only cellular support (no EU/Asia yet)
Final Verdict
⭐⭐⭐⭐⭐ 4.7 / 5
The Fi Series 3+ Smart Collar is more than a tracker—it’s a full behavioral assistant, health dashboard, and peace-of-mind device for responsible pet parents. If your dog’s safety and wellness matter to you (and they should), it’s hard to argue against the value this collar brings—even with the subscription.
Perfect for: Active dogs, tech-savvy owners, pet health monitoring
Not ideal for: Toy breeds under 10 lbs, users outside the US, those avoiding subscriptions
